Synermed International

Pioneers in Near Infrared Clinical Chemistry

UIBC - Unsaturated Iron-Binding Capacity

Catalog numbers:
IR 150-X1 x 250 mLR1
1 x 80 mLR2
IR 150-R3 x 250 mLR1
3 x 80 mLR2
911 Packaging - Contact Synermed

  • Liquid-Stable Ready-to-Use Reagents
  • Minimal Interference from Serum Bilirubin and Lipemia
  • Extended "On-Board" Stability
  • Proven Automated Methods
  • Usable with Dialysis Patients

UIBC Interference Comparison
The chromatic interference suppression of the Synermed® UIBC method is based upon the higher sensitivity of the chromogen used and the detection at a red wavelength, thus optimizing the signal to noise ratio.

Principles of the Reaction
Albumin binds with bromcresol green to form a colored complex. The absorbance of the complex is quantitated at 660 nm and is directly proportional to the albumin concentration in the sample.

In the Synermed UIBC reagent system, a known amount of ferrous iron is added, in excess, to the serum at an alkaline pH to enable saturation of the unoccupied iron binding sites on the transferrin molecule.

transferrin + Fe+2 -> transferrin-Fe complex + excess Fe +2

The ferrous ion that remains unbound to transferrin is then quantitated by complexing with the chromogen 3-(2-Pyridyl)-5,6-bis(2-[5-furylsulfonic Acid]-1,2,4-triazine to form a blue chromophore which absorbs in the near-infrared region of the spectrum. The absorbance of the blue iron-dye complex is proportional to UIBC concentration and is read spectrophotometrically at 600 nm.
excess Fe+2 + chromogen -> Fe+2-chromogen complex
(yellow) (blue)

Then by subtracting the amount of unbound iron thus measured from the total amount of iron originally added to the sample, the unsaturated iron-binding capacity may be determined.

To calculate the TIBC, perform a serum iron assay on the sample. Take the result obtained for the iron assay and add the UIBC result to obtain a value for TIBC.

Analytical Range
Most applications of the procedure have been found to be linear to 500µg/dL UIBC.

Expected Values
UIBC levels will vary with age, sex, and diet. It is strongly recommended that each laboratory establish an expected range for the local population. The normal range for TIBC in adults is reported to be: 250-400 µg/dL.

Specific Performance Characteristics
1.  The Synermed UIBC methodology was correlated to a widely accepted UIBC method. The calculated linear regression on 74 samples ranging from approximately 10 to 75 µmol/L (55 to 400 µg/dL) with Synermed results on the Y-axis is: Y = 0.97X - 0.7 with a correlation coefficient of 0.995.

2.  The sensitivity of the procedure is such that an absorbance change of 0.001 will detect as little as 1.1 µmol/L (6 µg/dL) UIBC.

3.  The average within run precision of the method was determined by assaying 30 samples of quality control material at two levels of UIBC concentration which provided the following results:

9.9 µmol/L (55 µg/dL)0.39 (2.2)4.0%
41.1 µmol/L (229 µg/dL)0.33 (2.6)1.1%
4.  The run to run reproducibility of the method as applied to an automated analyzer was determined from the values obtained by 5 replicate analyses of quality control material assayed over a 22 batch period. The following results were obtained:

10.3 µmol/L (57 µg/dL)0.46 (2.6)4.5%
43.0 µmol/L (240 µg/dL)1.20 (6.7)2.8%